I just had a stage in Japan 11.4 km dry with service before and directly after, and still had different tires left: medium, hard, 2x rain. So I took the rain tires.
The grip was about the same as with hard tires, but decreasing towards the end of the stage. And in the service they were shown as worn 1/3 red.
So: Good grip but heavy wear on dry asphalt!! (This is an improvement to Dirt Rally 2.0)
If you had to drive 2 stages now
-Japan 11.4km rain
-Japan 11,4Km dry
then of course rain tires are appropriate.
But if you have it the other way around
-Japan 11,4Km dry
-Japan 11.4km rain
then the tires are already used up after the first stage. Perhaps still the best choice, but perhaps not as ideal as for the first example.
A third example
-Japan 19,4Km dry
-Japan 11,4Km dry
-Japan 11.4km rain
And now? Which tires do we take? Maybe Medium tires better?